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This approach leverages JavaScript's built-in setTimeout and clearTimeout functions. We schedule a timeout to execute the function fn after t milliseconds, and we return a cancelFn that, when called, cancels this scheduled timeout.
In C, without a standard set of functions for asynchronous timeouts, it's less about algorithmic complexity and more about the overhead of managing threads, which varies based on the implementation details.
C does not have direct support for asynchronous delay management similar to setTimeout in JavaScript, particularly in standard libraries. Such functionality generally requires external libraries or platform-specific code for thread and timer management.
This alternative approach involves using Promises to manage asynchronous execution and potential cancelation. By wrapping the setTimeout within a Promise, we can have more control over its execution and cancelation by managing the Promise lifecycle.
Time Complexity and space complexity would depend on the specific threading mechanism and the use of synchronization primitives.
1using System;
2using System.Threading;
3using System.Threading.Tasks;
4
5public class PromiseTimeout
6{
7 public static async Task<Func<Task>> Cancellable(Action fn, int t)
8 {
9 var cts = new CancellationTokenSource();
10
11 Task.Delay(t, cts.Token).ContinueWith(_ =>
12 {
13 if (!cts.Token.IsCancellationRequested)
14 {
15 fn();
16 }
17 }, TaskScheduler.Current);
18
19 return async () =>
20 {
21 cts.Cancel();
22 await Task.CompletedTask;
23 };
24 }
25
26 public static async Task Main(string[] args)
27 {
28 Action fn = () => Console.WriteLine(10);
29 var cancel = await Cancellable(fn, 2000); // Trying with a delay-longer-than-task to show cancellation
30
31 // Simulate cancel call
32 Thread.Sleep(1000); // Less than 2000ms, hence should cancel
33 await cancel();
34 }
35}Using the Task-based Asynchronous Pattern (TAP) in C# allows us to emulate Promises. We use a combination of Task.Delay and a cancel token to manage execution within the specified delay, providing a canceling function that the caller can invoke.